Dear Liz: What are your thoughts on charitable giving? I hear about tithing (giving 10% of income) but would have real problems trying to maintain that commitment. That said, I’d like to become a regular donor to a reputable charity.

Answer: Most U.S. households give to charity, according to the Center on Philanthropy at Indiana University, but the average contribution rate for those who give is closer to 3% than 10%.

If you want to step up your charitable giving, take the time to plan and prioritize as you would any other part of your financial life.

Making larger donations to a few charities is typically better than scattershot donations to a bunch of causes, said Ken Berger, the president and chief executive of nonprofit watchdog Charity Navigator. Charities spend money to process donations, and those costs tend to eat up more of small donations, he said. A $100 donation to a single charity might incur $2 in processing costs, leaving $98 for good works, Berger noted. The same $100, spread among 10 charities, would require each to spend $2 for processing — leaving just $80.

Because smaller donations don’t benefit charities as much, some are tempted to increase their “yield” by selling your information to other charities or repeatedly hitting you up for additional contributions, Berger said. Giving more allows you more leverage to ask that your information not be sold and that the charity limit its appeals.

You can research charities at websites such as Charity Navigator and GuideStar to make sure you understand their finances and how effective they are in reaching their goals.

Finally, consider setting up automatic donations rather than rushing to make contributions at year’s end. Some companies have payroll deductions for charities, or you can set up a recurring charge on a credit or debit card. Making your contributions automatic helps ensure you can achieve your charitable giving goals. It’s like saving or “paying yourself first” — when you don’t have to constantly remind yourself to do it, it’s more likely to get done.

Dear Liz: I am wondering about what percentage of your income should your rent be. Ours at the moment is 35% just for rent, not including utilities or anything else.

Answer: In high-cost areas, people regularly pay 40% or more of their income on housing. That doesn’t mean it’s a good idea.

When you spend a big chunk of your income on rent or mortgage payments, there’s often too little left over to save for the future, pay off the debt of your past and live for today.

There are no hard-and-fast rules for what’s affordable, but limiting your housing costs to about 25% of your gross pay or 30% of your after-tax pay will help ensure that you have money left over for other goals. “Housing costs” include rent, utilities and renter’s insurance if you don’t own, or mortgage, property taxes, property insurance and utilities if you do.

If you’re much over these limits, you should look into ways to reduce your costs, earn more income or both. Otherwise, you’re likely to continue to struggle with an unbalanced budget.

Dear Liz: My spouse has tenure at a university. Given that one of us will always be employed, should we change the way we look at the amount of money we keep in an emergency fund or our risk tolerance for investments?

Answer: Even tenured professors can get fired or laid off. Tenure was designed to protect academic freedom, but professors can lose their jobs because of serious misconduct, incompetence or economic cutbacks, such as when a department is eliminated or a whole university is closed. About 2% of tenured faculty are dismissed in a typical year, according to the National Education Assn.’s Higher Education Department.

That’s more job security than in most occupations, of course. Your spouse also may have access to a defined benefit pension, which would give him or her a guaranteed income stream in retirement. Those factors mean you reasonably can take more risk with your other investments.

As for your emergency fund, you may be fine with savings equal to three months of expenses. But consider that if your spouse were to be dismissed, he or she probably would have a tough time finding an equivalent position. If the institution starts having financial difficulties or if there is any reason to suspect that he or she could be dismissed, a fatter fund could come in handy.

Dear Liz: A few years ago I finished paying off my debt and now am in the very low-risk credit category. I have savings equal to about three months’ worth of bills and am working to get that to six months’ worth. I’m wondering, though, about an emergency that may require me to pay in cash (such as a major power outage that disables debit or credit card systems, or the more likely event that I forget the ATM or credit card at home). How much cash should a person have on hand? Is there a magic number?

Answer: There’s no magic number. You’ll have to weigh the likelihood you’ll need the green, and the consequences of not having it when you need it, against the risk of loss or theft.

Many people find it’s a good idea to tuck a spare $20 into their wallet for emergencies, and perhaps another $20 in their cars if they’re in the habit of forgetting their wallets or their plastic.

Cash for a disaster is another matter. Power could go out for a week or more, or you may need to evacuate and pay for transportation and shelter at a time when card processing systems are disabled. A few hundred bucks in cash probably would be the minimum prudent reserve you’d want to keep in a secure place in your home. You may decide that you need more.

Dear Liz: My husband and I are recovering from a job loss four years ago. We used up all our savings and home equity. My husband is now employed, but we are struggling to keep ahead even with a salary of about $100,000. I was a stay-at-home mom for the first 10 years of our kids’ lives and now I work two part-time jobs to help with our expenses. We are trying to follow the 50/30/20 budget plan you recommend, but can’t seem to get our “must haves” — which are supposed to be no more than 50% of our after-tax income — down from 80% to 90%. Most of the rest goes for “wants,” such as the kids’ dance classes and soccer teams and for cellphones. We’re not saving anything although we’re trying to whittle down our credit card debt. I have tried several times to refinance our first and second mortgages and home equity line of credit but have found we don’t qualify because too much is owed on our modest three-bedroom, one-bath house, which has gone down significantly in value. We also have two car loans that are worth more than the cars, and the insurance is killing us. Amazingly enough, we have never been late on a payment. We just can’t get ahead. Did I mention that both kids need braces?

Answer: You clearly can’t afford your life, and things will only get worse if you don’t get your spending in line with your income.

Your first step should be to consult with a HUD-approved housing counselor, who can advise you of your mortgage options. You can get referrals from http://www.hud.gov. If your first mortgage is held by Fannie Mae or Freddie Mac, you may be able to refinance it through the federal government’s Home Affordable Refinance Program. Recent changes in the program have helped more underwater homeowners refinance. Even if you’ve been turned down by one lender, you can try with another. One way to search for HARP quotes is through Zillow’s online mortgage quote service at http://www.zillow.com/mortgage-rates/.

Government programs usually define an “affordable” payment as one that’s 31% or less of your gross income, but that may be too high for many families to comfortably handle. Ideally, your housing costs — including mortgage, property taxes and insurance — would consume no more than about 25% of your gross (pre-tax) income.

If you exhaust your options and can’t get your mortgage payments down to an affordable level, you should consider a short sale of your home. Moving is terribly disruptive and expensive but it’s better than letting a house sink your finances.

Then take a look at your cars. The average annual cost of owning a car is $8,946, according to AAA. You can make the argument that one car is a necessity, but having two is typically more of a convenience than a “must have.” Getting rid of one could dramatically lower your insurance and transportation costs.

Since you’re underwater on both, you’ll need to look at which is cheapest to operate and which is closest to being paid off. If they’re the same, then your choice is easier — you can work toward paying that car off faster so you can sell it. Otherwise, you’ll have to weigh which loan to target first.

Another way to get your budget balanced is to make more money. That may mean asking for more hours at your jobs or looking for opportunities that pay better.

‘Boomerang’ kids: Moving out again Household formation is on the rise and the kids who moved into their parents’ basements are finally able to move out on their own. Here’s what they, and their parents, need to know to avoid future boomerangs.

Simple retirement can be satisfying If you haven’t saved much for retirement, all is not lost as long as you’re willing to pursue a much simpler lifestyle than what you’re probably living now. One man who lives just such a life is happy he does.

Dear Liz: You’ve written frequently about the 50/30/20 budget, where no more than 50% of your after-tax income should be spent on “must haves” so that you have 30% for “wants” and 20% for debt repayment and savings. In which category would alimony fall? How about car payments?

Answer: Any expense that can’t be put off without serious consequences is considered a must-have. Since you could be sued or held in contempt of court for not paying your alimony, that would certainly qualify as a must-have. So too are all required loan payments, since failing to pay those will lead to credit card damage, possible lawsuits and, in the case of vehicles, repossession. Other must-haves include shelter costs, food, utilities, other transportation costs, insurance and child support.

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I’ve taken your toughest questions about money and answered them in a clear, easy-to-read format. This book can help you manage your spending, improve your credit and find the best way to pay off debt. It can help you make the right choices when you’re investing, paying for your children’s education and prioritizing your financial goals. I’ve also tackled the difficult, emotional side of money: how to get on the same page with your partner, cope with spendthrift children (or parents!) and talk about end-of-life issues that can be so difficult to discuss. (And if you think your family is dysfunctional about money, read Chapter 5…you’ll either find answers to your problems, or be grateful that your situation isn’t as bad as some of the ones described there!)

Dear Liz: My husband and I have been aggressively paying down our debts and plan to be debt free by this time next year. We’re devoting about 20% of our income to debt repayment and saving about 6% (not much, I know, but we’re young and just starting out). We were building an emergency fund and currently have enough money in it to cover only a few months of our expenses, since we had to dip into it recently for unexpected car repairs.

My husband just lost his job. I make enough that we would just barely be able to cover all of our minimum payments and our bills, but my employer lost its biggest client and I may be out of a job soon too. Should we continue to make the same debt payments, reduce the amount or make only minimum payments until we are both securely employed?

Answer: As soon as you know that unemployment is a possibility, you should begin to conserve cash. That means making only the minimum payments on your debt and cutting your expenses to the bone. Although the job picture is improving, the average duration of unemployment is still close to 40 weeks. That’s a long time to go without a paycheck.

When you’re both employed again, you should reconsider your financial priorities. Getting out of debt is a great goal, but not all debt is created equal. Paying off credit cards should typically be a high priority, but you needn’t be in as much of a rush to pay off federal student loans, car loans or mortgages, because the rates on these debts is typically fixed and relatively low. Instead, make sure you’re taking advantage of retirement savings opportunities and building up a cash cushion to tide you through the next financial setback.

Dear Liz: I have been granted a Chapter 7 bankruptcy discharge of all my debts. I’m now debt free and plan to stay that way. I’ve been saving like crazy and have enough to afford a cross-country driving trip to attend my son’s wedding. I’d like your advice on using prepaid debit cards to cover expenses such as fuel, food and lodging. My plan is to load each of three cards with an amount of money to cover each category of expense, based on my best research estimates, as a means of controlling how much I spend. If you feel this is a good plan, which would be the best brand of card to use?

Answer: Your determination to stay out of debt is admirable, but prepaid cards are problematic. You don’t have the same federally mandated consumer protections you have with a debit or a credit card, so merchant disputes or a lost or stolen card can wind up costing you big time.

Furthermore, these cards can be expensive. You often pay to activate the card, to load it with cash and to access the cash in transactions. Card comparison site NerdWallet.com studied 40 popular prepaid debit cards and found that the average card cost nearly $300 annually in basic fees. Monthly fees of up to $14.95 took the biggest toll, but $1 to $2 fees per transaction and for ATM use could easily cost a typical user more than $20 a month.

If you’re convinced prepaid cards are the best money-management tool for your situation, though, you might want to choose the American Express Bluebird, which was dramatically less expensive than its competitors in the NerdWallet study. The Amex card charges no monthly or per-transaction fees and allows for direct deposit. ATM withdrawals cost $2 apiece and cash reloads are just a buck, compared with an average of $4.50 with other cards.

Eventually you may want to look into getting a secured credit card to help you rebuild your credit scores, since prepaid cards won’t help with that. A secured card is one in which you make a deposit at the issuing bank, usually between $200 and $1,000, and get a card with credit limit equal to your deposit. You don’t need to carry a balance on these cards, but you do need to have and use credit if you want to rehabilitate your battered credit. NerdWallet recommends the secured cards issued by Orchard Bank and Capital One.